Background/Purpose:
Skin pathergy test (SPT) has a diagnostic value in Behçet’s syndrome (BS). There are different descriptions of the test which may effect its positivity rate. We aimed to compare different methods of SPT in patients with Behçet’s syndrome.
Methods:
Patients with BS who fulfilled the International Study Group Criteria for Behçet’s Disease and healthy volunteers were involved in the study. At 90% power (alpha= 0.5) for a 47% positivity rate for the oral method 20 patients and healthy volunteers were recruited (1). Pricks at five different sites were performed with a 20 gauge needle. i)subcutaneous ii) intradermal iii) intradermal with 0.1 cc of 0.09% saline solution iv) intravascular v) oral. The skin pathergy test was considered positive if there was a papule, pustule or oral aphtae (for the oral test) at the prick site after 48 hours. Sensitivity, specificity, positive and negative predictive values of SPT were calculated.
Results:
All patients with Behçet’s syndrome were positive for at least one SPT method where none of the healthy volunteers had a positive SPT. Among the five SPT methods subcutaneous and oral methods were most sensitive (70% and 60% respectively). All SPT methods showed 100% specificity and positive predictive value. Sensitivity and negative predictive values of SPTs are shown in Table 1.
Table 1. Sensitivity and negative predictive value of skin pathergy test methods
|
Skin Pathergy Methods |
Sensitivity |
Negative predictive value |
|
Subcutaneous |
%70 |
%77 |
|
Oral |
%60 |
%71 |
|
Intradermal |
%50 |
%67 |
|
Intradermal with saline |
%50 |
%67 |
|
Intravascular |
%20 |
%55 |
Conclusion:
Subcutaneous method is the most sensitive test among SPTs. Oral method may be an alternative for subcutaneous SPT.
Reference:
1. Sharquie KE, Al-Araji A, Hatem A.Oral pathergy test in Behçet’s disease Br J Dermatol. 2002 Jan;146(1):168-9
Disclosure:
A. Lacin,
None;
C. A. Uzun,
None;
Z. Gunendi,
None;
F. Gogus,
None.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/comparison-of-different-methods-of-skin-pathergy-test-in-patients-with-behcets-syndrome/